Australia's leading racehorse trainer Darren Weir is fighting for his career with stewards asking him to show why he should not be stood down pending an inquiry into electronic devices found in his stables.

Racing Victoria stewards charged Weir on Friday and withdrew all his horses from meetings over the weekend, including feature race runners at Caulfield on Saturday.

They then adjourned the show cause hearing until Monday afternoon.

Weir has been charged with possessing three taser-like devices known as jiggers and also with failing to give evidence to the stewards inquiry and conduct prejudicial to the image of racing.

RV opened the inquiry on Thursday, a day after they and Victoria Police officers from the sports integrity unit raided his stables at Warrnambool and Ballarat where they found the jiggers designed to give a horse an electric shock.

His assistant, licensed trainer Jarrod McLean who runs the Warrnambool stable, has also been charged with possession of a device and with failure to answer questions at the inquiry.

McLean has also been asked to show cause why he should not be stood down and his runner on Friday night at Moonee Valley was scratched.

RV's head of integrity, Jamie Stier, said while he realised the impact of the horses' withdrawals on owners, the seriousness of the case warranted the action as "the integrity of the sport is paramount."

"The stewards have imposed an interim order that all horses accepted to race from the Darren Weir and Jarrod McLean stables from tonight at Moonee Valley through until Monday be withdrawn with immediate effect pending the conduct of a show cause hearing," he said in a statement.

"The stewards are concerned about the seriousness of the threat posed by Mr Weir's and Mr McLean's alleged possession of an electronic apparatus. This is a significant issue in terms of animal welfare and racing integrity.

"The investigation has caused considerable public concern, and has generated considerable negative publicity, bringing into question the impact on the image, interests and integrity of racing of Mr Weir and Mr McLean's continued participation in racing pending the hearing of the charges."

A third man, stable employee Tyson Kermond, has been charged with failure to give evidence at the initial inquiry.

A former country trainer who has risen to be a five-time Melbourne premiership winner, Weir runs the biggest stable in Australia with more than 600 horses on the books and dozens of staff at both locations.

His biggest win so far came in the 2015 Melbourne Cup when 100-1 chance Prince Of Penzance claimed a famous victory for jockey Michelle Payne.

In the 2016/17 season, Weir became the first to train more than 400 Australian winners, winning 449 races, surpassing that in 2017/18 with 491 victories for prize money of more than $31 million

So far this season he has trained 265 winners who have earned almost $19 million prize money